Show trimming leaves more hoof on and a longer toe.
I've never seen a show horse with a rockered toe. AMHA rules state (or at least did the last I checked ) that a 45 degree angle is desirable for the front feet. I know, it's a little low for me too.
You would roll the toe in a driving horse, but never rocker. You want all the hoof your height classification can handle for movement. You would also take sole out to adjust height on a horse ( in that it allows you to remove more hoof wall ). In the average show horse (mini & classic shetland) you would trim the heels to the widest part of the frog and then adjust your lateral/medial balance to land flat.
Linda, got anything to add ?